Our yacht 'Footprints' relies on solar panels and a wind generator for battery charging. We do have input from our outboard but that is only about 4 amps and we do not use the motor often. We still manage to run all the usual electrics including a 12 volt compressor fridge, various marine radios, charging of the usual electronic devices and all of our lighting which is now LED. But this is sunny New Zealand where we have ideal solar panel charging conditions. We have close to 250 ah battery capacity and over 200 Watts charging capacity with the solar panels and wind generator. I do find that I need to actively orientate one of the panels which is movable towards the sun to get the best charging but when we are living on board and on a sunny day our batteries are usually fully charged again by mid afternoon. Our batteries are sealed AGM units so require no maintenance.

I think your 60 ah battery and 50 watt solar panel would only be enough if you are giving your boat only occasional usage so that the battery has a chance to recover before the next time you use the boat. If you are spending a few days on board you would need to significantly increase both the battery capacity and charging capacity otherwise the battery is going to die a very early death. The ability of the battery to retain charge also depends on the age of the battery.

I know, it depends...

Mariposa came with a 60ah battery and i've been running her (new) LED interior lights, charging the iPad and the iPhone, for a week now, with no recharging of the 60ah battery. The meter had dropped to 11.5 volts by today so i thought i better plug in the smart charger.

I've looked through the specs of the handful of devices i intend to use but i'm a little stumped. For example, i can't figure out how many amp hours the iPad will use if running Navionics full time on a passage. I guess too on passage i'll need to keep the hand-held VHF topped up for safety, and run the LED nav lights at night.

I've found a good price on this 50 watt solar panel and controller, which will fit neatly between hatches.

So i'm wondering about a bigger battery, whether or not the 50 watt solar panel will be enough, etc... I'd be grateful for some guidance. If i must get a bigger battery, i like the idea of having the 'main' battery, and the smaller battery as an emergency reserve, like motorcycle fuel tanks.

Mariposa has no motor yet, and when she does it will be a diminutive 6hp  four stroke outbaoard (anyone have one for sale?). So if there is to be any motor charging, it will only be one of those little charging coils that can be added to outboards.

Thanks for any tips and advice.

Matt Waite (Mariposa's new and happy owner).

P.S. Also, i gather that one can tell the state of charge of a battery by how many volts the meter is showing (i bought a cute little cig lighter volt meter that has 3 amp USB holes in it). Is there some kind of chart for this? Like 13 volts equals 95%, 12.5 volts equals 80%, 11.3 volts equals 30%, etc...